Question

Frequency-dependent property of graphene conductivity

Answer 1

Answer:

Explanation:

Many experiments have shown that electrical conductivity and dielectric permittivity of graphene-polymer nanocomposites are strongly dependent on the loading frequency, but at present no theory seems to be able to address the continuous influence of frequency. In this work we present a new effective-medium theory that is derived from the underlying physical processes including the effects of filler loading, aspect ratio, percolation threshold, interfacial tunneling, Maxwell-Wagner-Sillars polarization, and the extra frequency-affected electron hopping and Debye dielectric relaxation, to determine the loading-frequency dependence of these two fundamental properties. The theory is formulated in the context of complex conductivity under harmonic loading.

We highlight this new theory with an application to PVDF/xGnP nanocomposites, and demonstrate that the calculated conductivity and permittivity are in close agreement with the reported experimental data over the frequency range from 10² to 10⁷ Hz. We also show that the electrical conductivity tends to increase with frequency but the dielectric permittivity tends to decrease.